In general, bias reference circuits can be classified by the source of the voltage standard by which the bias currents are established. As noted in Analysis and Design of Analog Integrated Circuits by Paul R. Grey and Robert G. Meyer (John Wiley & Sons, 1977, pages 239-261), the most convenient standards are the V.sub.BE of a transistor, the thermal voltage, V.sub.T, and the breakdown voltage of a reverse-biased emitter-base junction of a transistor. While each of these voltage reference elements may be readily fabricated using conventional bipolar integrated circuit fabrication processes, it is significantly more difficult to fabricate the open-collector bipolar devices utilized in common V.sub.BE reference circuits using conventional MOS integrated circuit fabrication processes. On the other hand, the reverse-biased emitter-base junction or Zener diode reference circuit, although manufacturable in most MOS fabrication processes, generally requires supply voltages exceeding 7 to 8 volts, and tends to introduce significant amounts of noise under reverse-breakdown conditions.